Evolutionary psychology sais that men perform better in the presence of a woman. Men can't seem to help but try to impress women. The test that was used to demonstrate that effect is by giving men a creative challenge with and without a close-up picture of a pretty woman in the room.
With the picture present, men consistently perform better in finding solutions to creative challenges than a similar group of men without such a picture.
No such effect was seen with women performing similar tasks with a similar male picture.
So if you have a pure male group that needs to perform creative tasks, make sure you have the right photo's available as decoration...
Does that explain the omnipresent pirelli calendar in garages?